Landau's other credits range from James Mason's sinister henchman Leonard in Alfred Hitchcock's North by Northwest (1959) to Walks Stooped-Over in the epic Western spoof The Hallelujah Trail and Caiaphas in The Greatest Story Ever Told (both 1965), plus key parts in Woody Allen's Crimes and Misdemeanors (1988) and the film version of The X-Files (1997). Television credits include master of disguise Rollin Hand on Mission: Impossible (1966-1969) and guest spots on Columbo, Gunsmoke, The Outer Limits, and Without a Trace. Science fiction fans remember him best as Commander John Koenig on Space: 1999.

In animation, Landau voiced Mr. Rzykruski in Frankenweenie and the Scorpion in the 1990s Spider-Man series.